Antigen‐specific proliferation of porcine CD8αα cells to an extracellular bacterial pathogen

Abstract

+ cells were predominantly small. Addition of monoclonal antibodies (mAb) speci®c for either porcine major histocompatibility complex (MHC) class I or class II antigens diminished B. hyodysenteriae-speci®c proliferative responses whereas addition of mAb to porcine MHC II, but not porcine MHC I, reduced the CD8aa response. In vitro depletion of CD4 + cells by¯ow cytometric cell sorting diminished, but did not completely abrogate, the proliferative response of cells from vaccinated pigs to B. hyodysenteriae antigen stimulation. These results suggest that CD8aa cells are involved in recovery and possibly protection from a spirochaete-induced colitis of pigs; yet, this response appears to be partially dependent upon CD4 + cells.

Differences in lymphocyte subpopulations and cell counts before and after experimentally induced swine dysentery

“…In the present study, there was no increase in CD8â þ T cells in the swine dysentery group, which is in agreement with the findings of Waters et al (2000). The proliferation of CD8 þ cells in pigs with swine dysentery appears to be related to CD4 þ CD8 þ T cells and not to cytotoxic/suppressor T cells or ªä T cells, which also express the AEAE-homodimer of the CD8 receptor.…”

“…Thus, it could be speculated that animals with high levels of ªä T cells are more susceptible to infections in which CD8 þ cells and the production of IFN-ª are important for host immune defence. CD8 þ cells are a major responding subset in swine dysentery (Waters et al, 2000), and B. hyodysenteriae bacterin triggers production of IFN-ª in vitro by peripheral blood mononuclear cells (Waters et al, 1999a). Therefore, animals with large numbers of ªä T cells, and thus a downregulated CD8 þ T-cell response, may produce lower levels of IFN-ª.…”

“…The appearance of these antibodies has not been related to recovery from the disease (Rees et al, 1989a), but may be involved in protection against reinfection (Joens et al, 1979). Recovery from experimentally induced swine dysentery has been associated with an increased percentage of circulating CD8 þ CD4 À cells and an in vitro proliferate response of these cells against B. hyodysenteriae antigens (Waters et al, 2000). Immunization studies in pigs with pepsin-digested B. hyodysenteriae bacterin indicate an increase in both mucosal and peripheral blood CD8 þ cells (Waters et al, 1999b).…”

Brachyspira research – special issue on colonic spirochaetes of medical and veterinary significance

“…By comparing results from pigs that did or did not succumb to disease, the authors deduced that ªä T cells and CD8 þ cells may be associated with susceptibility to infection, whilst monocytes and CD4 þ CD8 þ T cells appear to be the major responding lymphocytes. These results add to previous information about CD8AEAE cell proliferation in pigs recovered from swine dysentery (Waters et al, 2000) and provide background information that could help to evaluate immunological responses to new vaccines being developed for swine dysentery. Jacobson and colleagues then describe efforts to reproduce swine dysentery in pigs reliably, and identify factors involved in disease susceptibility.…”

Immunostimulatory properties of a novel adjuvant administered with inactivated influenza virus vaccine

“…These cells are memory cells that proliferate specifically and produce IFN-γ [22,31,39] [36]. For the groups (Ag+BioMed) and (Ag+Alhydrogel), a decrease in relative percentage of doubly marked cells was observed on day 4 postchallenge.…”